0:01Skip to 0 minutes and 1 secondThe human genome can be thought of like a book. Just like a book DNA is made up of letters. Unlike the alphabet however it only has four letters; A T C and G. These letters are called bases and it is the ordering of these letters that spells out the genetic code As in a book DNA also contains words but these words are only 3 letters long. These words are called codons. The codons are put together to make up sentences. These sentences are our genes.

Imagining the genome as a book

The human genome is complex, but for the sake of simplicity it can be imagined like a book: our DNA is composed of letters (chemical bases). Put together, these form words (codons), which make up sentences (genes), which are organised into chapters (chromosomes). When this book is read, the genes provide the instructions for our cells, telling them which amino acids are needed to form a protein.